The invention relates to a crushing device or comminutor for cuttings or chips from machining operations.
Crushing devices of such a kind are known and comprise a coarse breaking mechanism and a fine breaking mechanism. A hopper into which the cuttings can be filled, is arranged above the coarse breaking mechanism. First, the cuttings are torn by means of the coarse breaking mechanism, and then they are broken into short cuttings by the fine breaking mechanism. Afterwards, the short cuttings are discharged via a chute.
It sometimes happens that coarse pieces like, for example, iron pieces or tool parts are introduced into the hopper. Such coarse pieces are grasped by the coarse breaking mechanism and can cause a blockage of the entire apparatus. To remove such coarse pieces, it is necessary to open a window and to take the piece out of the system manually, which requires a considerable machine down-time. Furthermore, it happens occasionally that the fine breaking mechanism has already been damaged by the coarse piece, so that it has to be replaced.
The object underlying this invention is to improve a chip-crushing device of the kind described above in such a way that any coarse pieces which enter the crusher are detected before damage to the crushing device occurs.
Another object of the invention is to provide a crushing device in which coarse pieces which could damage the crusher are prevented from being caught in the fine breaking mechanism.
It is also an object of the invention to provide a crushing device which can automatically respond to entry of coarse pieces into the device and discharge such coarse pieces before they can jam or block the crusher.
These and other objects have been achieved in accordance with the present invention by providing a crushing device for cuttings, comprising a hopper for filling cuttings into the device, a tearing arm for coarse breaking of the cuttings, and a fine breaking mechanism, wherein the fine breaking mechanism comprises at least one centrally arranged grinding mechanism with a rotating blade head which operatively interacts with stationary teeth disposed peripherally around the grinding mechanism; the stationary teeth are disposed on at least two support segments; and the at least two support segments are movable in such a way that if a coarse piece enters the crushing device, the segments can be separated from the blade head, so that the coarse piece can be discharged from the crushing device.
A significant advantage of the present invention is that in the fine breaking mechanism, which comprises a grinding mechanism that operatively interacts with stationary teeth disposed on at least two support segments, the support segments are movable in such a way that they can be separated from the blade head of the grinding mechanism if any coarse pieces are introduced into the crusher, so that such coarse pieces are discharged from the crusher. It thus becomes unnecessary to provide any additional openings on the hopper for removal of coarse pieces. The coarse pieces can fall downwards into a container provided for them. Any damage to the blade head or grinding mechanism of the fine breaking mechanism is effectively prevented through opening of the stationary tooth supporting segments.
In accordance with one preferred embodiment of the invention, a flap is arranged below or at the side of the blade head onto which the coarse pieces are ejected.
In accordance with another preferred embodiment of the invention, two or more stationary tooth supporting segments are arranged to be movable outwardly in star shape. Thus, the grinding mechanism can be opened entirely, allowing coarse pieces to be ejected or discharged. The stationary tooth supporting segments can be arranged on slidable stages which can be driven either electrically or pneumatically.
It is likewise possible to drive the slidable stages hydraulically or to connect them to the driving motor by means of mechanical link rods. In the latter case, the rods open the grinding mechanism upon reversal of the driving motor.
According to a further exemplified embodiment, a sensor may be provided for sensing coarse pieces within the hopper and generating a control signal so that the stationary tooth bearing segments will open.
Alternatively, it is possible to recognize a coarse piece and then generate the respective control signals by monitoring changes in the torque of the grinding mechanism. It is even possible to detect the presence of a coarse piece by monitoring the load of the motor or the hydraulic drive and generating a corresponding control signal in response to a detected overload condition in order to activate the ejection of the coarse pieces.
These and other features of preferred embodiments of the invention, in addition to being set forth in the claims, are also disclosed in the specification and/or in the drawings, and the individual features each may be implemented in embodiments of the invention either singly or in the form of subcombinations of two or more features and can be applied to other fields of use and may constitute advantageous, separately protectable constructions for which protection is also claimed.